What are the different models on offer?

The entry level model is the Apple Watch Sport, which comes with an aluminium casing. Then there's the "regular" stainless steel Apple Watch and the ultra-premium 18-carat gold Apple Watch Edition.

Each watch comes in a version that's 38mm across the longest part of the watch face (well, technically 38.6mm but who is counting) and another one that's 42mm.

How many choices are there in terms of straps?

There are three different types of leather straps, a link bracelet, a Milanese loop and a strap made form high-performance synthetic rubber - in a range of colours.

What does the Apple Watch do that’s different from a regular watch?

In addition to telling the time through a range of customisable clock faces, Apple Watch offers notifications, health and fitness tracking and new ways to communicate with others. You can send a tap, sketch or even your heartbeat to someone else with an Apple Watch.